Icons arent displayed anymore

Hi support team,

after I activated the plugin, every Icon was displayed as black or white square on Firefox Chrome and Edge. You could only see the icons them properly on safari. Even deactivating or uninstalling the plugin didn’t help. Can you tell me what exactly is changed or blocked when i activate this Plugin so i can undo those changes?

Best regards.

The page I need help with: [log in to see the link]